1. Field of the Invention
The present invention concerns direct current converters and more particularly converters for use in electrically propelled vehicles such as trolleybuses.
2. Description of the Prior Art
In the field of solid-state power conversion, devices for converting direct current power to alternating current power based on single-phase, three-phase or multi-phase (with a number of phases other than three) converters are known in themselves.
Also known in themselves are devices for converting alternating current power into direct current power using single-phase, three-phase or multi-phase rectifiers.
Also known in itself is a device for converting direct current power into direct current power, with galvanic isolation, using single-phase, three-phase or multi-phase inverter-rectifiers combining the previous two structures with a transformer between the inverter system of the direct current to alternating current converter device and the rectifier system of the alternating current to direct current converter device.
This type of converter has the drawback of being unidirectional, transferring energy in one direction only.
Another drawback of a device of the above kind is that the rectified output voltage cannot under any circumstances exceed the floating voltage of the transformer secondary.
The invention aims to remedy the drawbacks of the prior art devices by creating a direct current to direct current converter device with galvanic isolation which is of relatively simple construction, reversible and can provide rectified output voltages greater than the floating voltage of the secondary winding of the transformer.